ok, let's try an approach from a different perspective:
can you confirm that ps cs6 is working correctly on dual screens with one screen connected to AMD Radeon HD 6700, PCI Express and one screen connected Intel HD Graphics 4000, OnBoard? Did you test this circumstances yourself? How can you argue that it is not a bug in Adobe's software?
Because there are quite a lot people around in the internet who have these problems if two different GPU's are used.
many thanks!